We request funds to purchase an automated oligodeoxynucleotide synthesizer and ancillary equipment. Synthetic oligodeoxynucleotides of defined sequence will be used by the two Co-PI"s and twelve co-investigators in diverse research projects that delve into the structure, function and expression of genes. Each project requires synthetic oligodeoxynucleotides either for specific hybridization probes for identifying unique genes following cloning via recombinant DNA technology or for site-specific mutagenesis to probe the function of regulatory or structural gene sequences. Oligodeoxynucleotide sequences determined from amino acid sequences of specific proteins will be synthesized and used as hybridization probes to identify clone genes or mRNA sequences for T cell antigen recognition molecules, the LDL receptor protein, brain-region specific proteins, Treponema pallidum antigens, transforming growth factors, and adrenal cytochrome P-450's. Oligodeoxynucleotides will be used to introduce unique nucleotide changes in cloned gene sequences to a) identify sequence requirements for regulated expression of genes encoding the mammalian HMG-CoA reductase, yeast heat shock proteins and yeast alcohol dehydrogenase, b) identify nucleotide sequence requirements for mitochondrial mRNA and tRNA processing, and c) investigate enzyme structure-function relationships through selective amino acid substitutions.